Thermostatic mounting structure for electron discharge device



THERMOSTATEC MOUNTING STRUCTURE FOR ELECTRON DISCHARGE DEVICE Filed July23. 1956 27, 1959 P BEAVENBOER 2,910,601

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IN VEN TOR: PIE TER BRAVENEOER arrnannros'mnc MOUNTING i STRUCTURE. FOR

- "EIZECTRONDISCHARGEDEVICE .FPieter Bravenboer,.Eindhoven, Netherlands,\assignor," by

mesne assignments, to North American Philips Company, Inc., New York,N.Y., a corporation of Delaware Application July 23, 1956, Serial No.599,644

Claims priority, application Netherlands July 27, 1955 1 Claim. (Cl.313) This invention relates to means for mounting a thermostat onelectron discharge devices, such as ignitrons, having a double-walledwater jacket constructed integrally with the tube.

In tubes which are required to carry large electric currents, of whichthe ignitron is an excellent example, it is necessary to provide meansfor cooling the tube wall. For this purpose it is common to provide adouble-walled structure, the inner wall enclosing the operating tubeelements and the outer wall cooperating with the inner wall to form awater jacket. Water in sufiicient quantity to keep the inner wall belowa predetermined temperature at all times flows through the space betweenthe inner and outer walls. However, ignitrons so constructed arefrequently used in welding apparatus where the current load is notcontinuous and where it is unnecessary to provide a continuous flow ofwater through the water jacket, although it is essential that the supplyof water during periods of peak current be sufficient to keep the innerwall of the tube below the rated temperature. In order to adjust theflow of water to the cooling requirement of thetube, a thermostat may beattached to the tube to operate a water supply valve during the periodswhen the inner wall exceeds the rated temperature.

The primary object of the invention is to provide good thermalconducting means between the inner wall of an integrally water-jacketedtube and a thermostat outside the water jacket. It is an additionalobject to provide such thermal conducting means in a form immune to theforms of scale or corrosion and to seal the thermal conducting meansinto the water jacket so as not to require gaskets which are subject toleakage.

The present invention comprises a block of thermally conductive materialsecurely attached to the inner wall of the electron discharge device andextending out to the inner surface of the outer wall. Outside of theouter wall is a second block of thermally conductive material which isin intimate contact with the outer wall immediately over the inner blockand which is preferably provided-with direct thermal contacting pins orscrews extending through the outer wall and into the inner block andsoldered in place to prevent leakage. The outer block serves as athermal contacting element for a thermostat and also as a base on whichthe thermostat can be mounted.

The invention will be further described in connection with the drawingsin which:

Fig. l is a partial cross-sectional view of a doublewalled electrondischarge device including thermal contacting elements constructedaccording to the invention;

Fig. 2 is a side cross-sectional view of the elements in Fig. 1;

Fig. 3 shows a complete ignitron including the thermostat mounting blockof the invention.

In Fig. 1 the wall 1 is the inner wall'of an electron discharge devicesuch as an ignitron and is the wall which ice 1 tmustlbe maintained.below ar critical temperature. Reference. character-.2 .designates.aconcentric outer wall which -...cooperates with the-inner walll:toforma water jacket completely surrounding .the inner wall 1. toftgoodthermal conductingmaterial, such as copper,

A slab 3 made to fit the shape ofrthe-outerwallszaandsattached theretoby means of a pair of pins, or bolts 4 which extend through the outerwall 2 into an inner cylindrical segment. 5, which is also made of goodthermal conducting material such as copper. The pins or bolts 4 arepreferably soldered or otherwise sealed to the outer wall 2 so astoprevent water leakage.

A thermostat 6 is clamped to the slab 3 by means of a strap 7 which issecured by a pair of bolts 8. Thermostat 6 is a well-known type ofthermostat and is provided with electrical connections 9 mounted on aterminal block 10. These electrical connections may be connected torelays to control the flow of water through the space between the innerwall 1 and the outer wall 2 in response to temperature changes of theinner wall caused by variations in the current drawn through the tube.

Fig. 2 is a cross sectional view of these elements which form permanentparts of the tube but does not show the thermostat and its associatedelements. It will be observed in Fig. 2 that the cylindrical segment 5is pro vided with a pair of flanges 11 and 12 by which it may be Weldedto the inner wall 1 of the discharge device in order to assure goodthermal contact to the inner wall and at the same time to prevent thepossibility that scale may be formed between segment 5 and wall 1 whichwould interfere with the thermal connection and would give falsereadings on the thermostat shown in Fig. 1. It is important to provide agood thermal connection from the inner wall 1 to the slab 3, although itis desirable that the thermal contact be not so perfect as to causeexcessively slow response to an increased supply of cooling water. Thismay be explained as follows. The interval side of the inner wall willhave a certain temperature to maintain the vapour within the tube. Theouter side should have lower temperature to make possible a heat flow tothe exterior. If new the thermal contact between the slab 3 and the wall1 would be perfect, the temperature of the cooling water would notinfluence the temperature of the slab 3, because the water contacts the,segment 5 only at the edges which have a surface area that is smallcompared to that of the segment itself. This difficulty is avoided bymaking the thermal contact less perfect. a

Fig. 3 shows a side view of a complete ignitron incorporating thethermostat mounting elements shown in Figs. 1 and 2 and in additionshowing an inlet pipe 13 and outlet pipe 14 to be connected to a sourceof cooling water.

Although the invention has been described in terms of single embodiment,it will beobvious to those skilled in the art modification may be madetherein within the scope of the following claim.

What is claimed is: 1

An electron discharge device comprising an inner wall which must be keptbelow a predetermined temperature; an outer wall cooperating with saidinner wall to form a water-tight compartment through which water mayflow to cool the inner wall; and a contact structure adapted to providethermal contact between the inner and outer walls and a thermallyresponsive member, said contact structure comprising: an inner segmentof thermally conductive material attached to the inner wall to make goodthermal contact therewith, said segment having a plurality of flangessecured to the inner wall to further provide good thermal contactbetween said segment and A 0 the inner wall and to prevent the formationof scale References Cited in the file of patent between the inner walland the segment; an outer segment of thermally conductive materialattached to the outer wall to make good thermal contact therewith and tosupport a thermally responsive member in good thermal between, saidlatter means being sealed to said outer wall to prevent water leakage.

UNITED'STATES PATENTS Kercher Aug. 8, 1916 Schwimmer Feb. 16, 1926Springer' L Aug. 13, 1929 Spencer July 4, 1933 Huber June 20, 1939Pearson May 23, 1944 Keating Aug. 5, 1958

